Slider for VLC not working like expected

I borrowed the concept of a slider for the VLC player from @vipersonic which can be found here:

My problem is that the slider won't go back completely to the beginning of the video, when I slide back. It always only goes back to 30sec - 3min, but never to 0 sec (as can be seen in the screenshot below). Can someone tell me what the problem might be?
Thanks! :slight_smile: